LCD Clear

[NadirHajiyev]

Hello. I tried write a program to display current voltage of battery.
But when I run it in brick screen is not cleaned. Could you help me to fix this error?
Here is my code. Thanks a lot.

Code: Select all

import javax.microedition.lcdui.Graphics;

import lejos.nxt.Battery;
import lejos.nxt.Button;
import lejos.nxt.LCD;
public class GetVoltByGUI {
   public static void main(String[] args){
      
      Graphics g = new Graphics();
      final int lcdWidth = LCD.SCREEN_WIDTH;
      final int lcdHeight = LCD.SCREEN_HEIGHT;
      
      while(!Button.ESCAPE.isPressed()){
         while(!Button.ENTER.isPressed()){
            g.drawString("Do you want", lcdWidth/2, lcdHeight/4, Graphics.HCENTER|Graphics.BASELINE);
            g.drawString("to see voltage of", lcdWidth/2, lcdHeight/4+8, Graphics.HCENTER|Graphics.BASELINE);
            g.drawString("batery?", lcdWidth/2, lcdHeight/4+16, Graphics.HCENTER|Graphics.BASELINE);
         }
         LCD.clearDisplay();
         if(Button.ENTER.isPressed()){
            g.drawString(String.valueOf((Battery.getVoltageMilliVolt())), lcdWidth/2, lcdHeight/4, Graphics.HCENTER|Graphics.BASELINE);
         }
      }
      
   }
}


[gloomyandy]

What exactly do you expect to happen and what exactly happens. It is unlikely that anyone will actually test your code to see what happens, so it will help people to help you if you describe how you want the code to work and what it is actually doing. So when you say the displayed is not cleared what do you mean what remains on the screen and when?

[NadirHajiyev]

Thanks.
I solve this problem by adding

Code: Select all

Thread.sleep();

to my code.
Next time I`ll do my best to describe my question.
The problem was that:
first the question (do you want to...) is displayed and when "enter" is pressed first clear display then it shows current battery voltage.
But in practice the display is not clear.

[matthias]

you also might want to put the 3 drawString calls before the while loop. (you are writing the same text to the display over and over again, as long as no button is pressed...)

Code: Select all

        g.drawString("Do you want", lcdWidth/2, lcdHeight/4, Graphics.HCENTER|Graphics.BASELINE);
        g.drawString("to see voltage of", lcdWidth/2, lcdHeight/4+8, Graphics.HCENTER|Graphics.BASELINE);
        g.drawString("batery?", lcdWidth/2, lcdHeight/4+16, Graphics.HCENTER|Graphics.BASELINE);
        while(!Button.ENTER.isPressed());

Also: why dont you use the LCD.drawString method instead of the Graphics.drawString method?